1. Field of the Invention
The invention relates to an energy-saving fluorescent lamp, and more particularly to a quick start shielded energy-saving fluorescent lamp, as well as a method for producing the same.
2. Description of the Related Art
Energy-saving fluorescent lamps, particularly shielded energy-saving fluorescent lamps, which are very similar to incandescent lamps in appearance, have aroused more and more attention. However, these lamps have a common disadvantage at work, i.e., it takes a long time to achieve the rated brightness. The disadvantage is decided by the inherent characteristics of conventional shielded energy-saving fluorescent lamps. The shade blocks the diffusion of the lamp heat, so the lamps have higher temperature than those without a shade (naked lamps). The working principle of the energy-saving fluorescent lamps is to generate light by maintaining low pressure mercury vapor. To achieve a high luminous efficiency, the mercury vapor pressure must be maintained at a reasonable value. When lamps work at high temperature, to obtain a suitable mercury vapor pressure, high temperature amalgam must be used. Upon turning on the lamps, the initial temperature is low, so is the mercury vapor pressure generated by the high temperature amalgam, the lamps have low brightness. With the increase of the lamp temperature, the mercury vapor pressure and the brightness increase, so does the luminous flux. Generally, it takes 60-120 seconds to reach 80% of the rated luminous flux. Thus, conventional shielded fluorescent lamps cannot be lighted immediately just like an incandescent lamp. The brightness is decided by the mercury vapor pressure, and the mercury vapor pressure is decided by a cold-end temperature. Thus, the light brightness is finally decided by the cold-end temperature.
Because conventional fluorescent lamps adopt high temperature amalgam, they cannot be lighted immediately. Thus, to make the shielded fluorescent lamps lighted quickly, a sufficiently low temperature cold end can be disposed in the lamps so that the low temperature amalgam can be used.